It is not needed to use the WSO2 ESB as a PEP. You can write you own PEP to integrate with your application. As an example, if your application is an java web application, you can write your own PEP client to call the EntitlementService
.
Advantage of using WSO2 ESB is that, It can act as Security Gateway for you all type of requests. It can do authentication/security protocol switching and more.. It has an extensible architecture.. If your all idea is to only to use WSO2ESB as PEP, I do not think it is worth. ESB is also calling EntitlementService
of the WSO2IS. Therefore you can directly call it from your application. You can write simple PEP client using java. You can find java client from here and you can integrate it with your application as PEP. There are some place that have been done it. Please find one from here. In his sample, command line client calling the EntitlementService